Question

Assertion: The sides of a triangle are 3cm, 4cm and 5cm. Its area is $6c{m}^2$

Reason: If 2s = (a + b + c), where a, b, c are the sides of a triangle, then area

$=\sqrt{(s-a)(s-b)(s-c)}$

Which of the following is correct?

• A. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
• B. Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
• C. The assertion is correct but Reason is incorrect.
• D. The assertion is incorrect but Reason is correct.

Answer 1

The correct option is C

The assertion is correct but Reason is incorrect.

$s=\frac{a+b+c}{2}\Rightarrow s=\frac{3+4+5}{2}=6cm$

Area $=\sqrt{s(s-a)(s-b)(s-c)}$

$=\sqrt{\left(6\right)(6-3)(6-4)(6-5)}$

$=\sqrt{\left(6\right)\left(3\right)\left(2\right)\left(1\right)}=6c{m}^2$

Assertion is true but Reason is false.